A multiple coordinate measuring machine has measuring slides displaceable along the individual measuring coordinates. One of the slides carries a measuring arm projecting away from it. As a result of the measuring arm shape, a probe member or sensor fixed to the arm free end can be moved to different points on a measured object, without the measuring slide colliding with the object. The measuring arm must extend a minimum distance from the slide to provide an adequate measuring volume within which the probe member is movable.
Multiple coordinate measuring machines are marketed by a number of companies, a selection of the machines being given in the Journal "Idee", 12/82, p. 31. A partially sectioned perspective view on page 26 of this Journal illustrates a measuring arm having inductive primary elements providing displacement transducers for three coordinates in a rigid casing. The complex manufacture and high costs for constructing such measuring arm as a measuring head are apparent from the drawing. This conventional measuring arm creates a risk that the casing will collide with the object to be measured preventing measurement with the required degree of accuracy as a result of the damage to the machine. The movement of the probe member relative to the object to be measured occurs by manual remote control and requires considerable time and skill.